Hand trucks having two wheels operatively placed between a toe plate and an elongated handle extending generally perpendicularly from each other are commonly used in warehouses and construction sites for conveying material from one location to another.
Elongated articles are conventionally loaded on such hand trucks with their longitudinal axes extending perpendicularly to the direction of travel of the hand truck, and it is sometimes necessary to convey the long articles through a restricted opening such as an ordinary 3 foot wide doorway which will accomodate the hand truck but will not accomodate the length of its transversely extending cargo.
In such instances, it is accepted practice to remove the articles from the hand truck, orient them so they extend parallel to the direction of travel through the doorway, and carry them through the doorway independently of the hand truck. After the unloaded hand truck is pushed through the doorway, it is reloaded with the elongated articles again extending perpendicularly to the path of travel and moved to its destination, or to the next doorway where the unloading and reloading is repeated.
U.S. Pat. No. 3,666,285 issued May 30, 1972 to William J. Fertig for AUXILIARY MOVEMENT MEANS FOR HAND TRUCKS represents an attempt to solve the problem of having to unload and reload a hand truck to get its elongated cargo through a doorway too narrow to accomodate the length of its transversely extending cargo. Fertig provides the usual two wheels for the hand truck and auxiliary wheels normally supported above the floor but selectively movable into operative position engaging the floor in position to move the hand truck in a direction parallel with the longitudinal axis of its cargo.
Fertig accomplishes the transition from the primary wheels to the auxiliary wheels by first positioning the auxiliary wheels in operative position and then tilting the truck rearwardly to transfer the weight of the truck and its contents from the primary wheels to the auxiliary wheels. Only two auxiliary wheels are provided by Fertig and they are located directly behind the primary wheels in use so that one of the auxiliary wheels follows the other when they are conveying the load, and this necessitates a careful balancing of the truck and its load while traveling on the pair of auxiliary wheels. The need to position the auxiliary wheels for use is time consuming and the need to balance the long and sometimes heavy load on the auxiliary wheels makes it difficult, especially for one person, to move the loaded hand truck through a doorway.
U.S. Pat. No. 4,460,189 issued July 17, 1984 to Frederick Goff for MULTI-DIRECTIONAL PORTABLE HAND TRUCK represents a more recent effort to solve the problem of getting a hand truck through a doorway too narrow to accomodate the length of transversely loaded articles. Goff provides dome-shaped wheels and an indexing mechanism for orienting the wheels to move the truck in a desired direction. It is necessary to stop the truck and individually orient each of the wheels from its position for normal travel in a direction perpendicular to the longitudinal axis of its cargo into a selected position for moving the truck and its cargo in a direction parallel with the longitudinal axis of the cargo. This is a time consuming and expensive procedure which is overcome by the present invention.